We are investigating polyfunctional catalysis, which is an important basis for the remarkable catalytic activity and selectivity of enzyems. In order to understand what is going on as well as possible we start with cases that are as simple as possible. The simplest feasible reactions are studied and mono-functional catalysis is studied (if it has not already been studied by others) before bifunctional catalysis. The reactions we have studied most are alpha-hydrogen exchange reactions of aldehydes and ketones (models for epimerases, aldolases, dehydrases, carboxylases, etc.). We have also studied dealdolization, the rearrangement of phenylglyoxal, and ester cleavage (as a model for serine enzyme reactions). All the catalysts studied so far have been various types of amines. We have obtained catalytic activity comparable to that of a natural enzyme in one case and also marked stereoselectivity. Although a number of instances of bifunctional catalysis have been observed, no trifunctional or higher order catalysis have been established yet.